This question may be old but there is an updated way of accomplishing this. When working in the sandbox environment, the option now also exists to have flexible item configurations and realistic-looking data. By using the user_custom and a json password that conforms to a schema.
For example
username: user_custom
password:
{
"override_accounts": [
{
"type": "depository",
"subtype": "checking",
"transactions": [
{
"date_transacted": "2019-10-01",
"date_posted": "2019-10-03",
"currency": "USD",
"amount": 100,
"description": "1 year Netflix subscription"
},
{
"date_transacted": "2019-10-01",
"date_posted": "2019-10-02",
"currency": "USD",
"amount": 100,
"description": "1 year mobile subscription"
}
]
}
]
}